BACKGROUND: Carbapenems are the antibiotics of last-resort for the treatment of bacterial infections caused by multidrug-resistant organisms. The emergence of resistance is a critical and worrisome problem for clinicians and patients. Carbapenem-resistant Enterobacterales (CRE) are spreading globally, are associated with an increased frequency of reported outbreaks in many regions, and are becoming endemic in many others. OBJECTIVES: Determine the molecular epidemiology of CRE isolates from various regions of Saudi Arabia to identify the genes encoding resistance and their clones for a better understanding of the epidemio-logical origin and national spread. DESIGN: Multicenter, cross-sectional, laboratory-based study. SETTING: Samples were collected from 13 Ministry of Health tertiary-care hospitals from five different regions of Saudi Arabia. METHODS: Isolates were tested using the GeneXpert molecular platform to classify CRE. MAIN OUTCOME MEASURES: Prevalence of various types of CRE in Saudi Arabia. SAMPLE SIZE: 519 carbapenem-resistant isolates. RESULT: Of 519 isolates, 440 (84.7%) were positive for CRE, with Klebsiella pneumoniae (410/456, 90%) being the most commonly isolated pathogen. The distribution of the CRE-positive K pneumoniae resistance genes was as follows: OXA-48 (n=292, 71.2%), NDM-1 (n=85, 20.7%), and NDM+OXA-48 (n=33, 8%). The highest percentage of a single blaOXA-48 gene was detected in the central and eastern regions (77%), while the bla NDM -gene was the predominant type in the northern region (27%). The southern regions showed the lowest percentages for harboring both blaOXA-48 and bla NDM genes (4%), while the western region isolates showed the highest percentage of harboring both genes (14%). CONCLUSION: The results illustrate the importance of molecular characterization of CRE isolates for patient care and infection prevention and control. Larger multicenter studies are needed to critically evaluate the risk factors and trends over time to understand the dynamics of spread and effective methods of control. LIMITATIONS: Lack of phenotypic susceptibility and clinical data. CONFLICT OF INTEREST: None.

Background and objectivesThe emergence of methicillin-resistant Staphylococcus aureus (MRSA) infections among previously healthy persons in community settings, without exposure to health care facilities, has been noted recently. Colonization rates of community-associated MRSA (CA-MRSA) have been reported to range from 0 to 9.2 percent. The nose and open skin areas are considered the most important sites for colonization. The aim of our study was to assess the prevalence and to describe the antibiotic susceptibility pattern of CA-MRSA among outpatient children.Patients and methodsWe prospectively screened every third consecutive child presenting to our pediatric emergency department of King Saud Medical City, a 275 bed tertiary care teaching hospital in Riyadh, Saudi Arabia, from March through July 2015.ResultsWe analyzed a total of 830 screening results (n = 478 males, 57.6%). Most of the screened patients were from Riyadh (n = 824, 99.3%). A total of 164 (19.8%) were found to be colonized with S. aureus, and of these 38 (4.6%) with MRSA. Thus, the MRSA rate amongst all S. aureus carriers was 23.2%. All MRSA were susceptible to vancomycin, (94.7%) were susceptible to linezolid, (65.8%) to clindamycin, and (89.5%) to trimethoprim/sulfamethoxazole.ConclusionThe rate of MRSA carriage among children in Riyadh province was within the range reported internationally. As the MRSA rate among S. aureus infected children was 23.2%, empirical MRSA coverage should be considered in children with suspected S. aureus infections.

We present the case of 31-year-old man who developed hospital-acquired pneumonia in the intensive care unit. Pathogens were identified to be carbapenem-resistant isolates of Providencia stuartii and Klebsiella pneumoniae. The patient was treated with an extended infusion of double-dose meropenem (targeting the carbapenem-resistant P. stuartii) and colistin (targeting the carbapenem-resistant K. pneumoniae) for 2 weeks. The patient's disease responded well to the prescribed regimen; his chest X-ray became normal, and all other signs of infection subsided. To our knowledge, this is the first description of the emergence of carbapenem-resistant P. stuartii due to AmpC hyperproduction in Saudi Arabia.

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